Continued support is requested for a project which will demonstrate the applicability of Fourier transform mass spectrometry to high resolution accurate mass analysis of ion with masses in the 1,500-20,000 dalton range. This will be accomplished using (1) laser desorption; (2) cesium ion bombardment; (3) fast atom bombardment; (4) thermospray techniques for sample volatilization in conjunction with a dual cell differentially-pumped Fourier transform mass spectrometer and an 8T magnet. It is expected that unprecedented high mass resolution at m/z 20,000 or above will be demonstrated. Furthermore, the relative sensitivity, accuracy, and resolution will be determined in comparison with results to be obtained with the same samples on a high performance VG Instruments ABZ-1HF double focussing mass spectrometer. The applicability of the methodologies developed to bipolymer analyses (e.g., polypeptides and polysugars) will be investigated.